The times of floral initiation of Bromus inermis varieties Carlton (northern-type) and Redpatch (southern-type) and B. pumpellianus from three latitudes were determined under field conditions at Beaverlodge, Alberta. This was done by recording developmental stage of apical meristems of tillers during the spring and fall. A dates of seeding trial involving Carlton and Redpatch was also undertaken. It was found that both types of B. inermis underwent floral initiation in the spring at Beaverlodge. Both types started development after April 26 of 1971 and 1972. It was concluded that temperature was the major factor governing the onset of floral development in B. inermis. The B. pumpellianus accessions all underwent floral initiation in the fall, prior to soil freeze-up. Polar bromegrass, which has both B. inermis and B. pumpellianus ancestry, behaved in a similar manner. There were small differences in the times at which floral development started. It is probable that day length is the prime factor governing floral initiation of B. pumpellianus and Polar bromegrass in the fall. On the basis of one year's seed yield data, it was suggested that Carlton and Redpatch should be seeded after mid-May but before mid-July when grown as seed crops at Beaverlodge. It was also found that plants which produced seed in the year following seeding had developed more than one tiller prior to freeze-up in the year of seeding. Larvae of Hylemya sp. were found to be damaging tiller bases and apical meristems of Bromus spp. The extent of the larval infestation varied seasonally and yearly. / Land and Food Systems, Faculty of / Graduate

Bromegrass species (<i>Bromus</i>) can produce high forage yields under the short growing season of western Canada and have excellent nutritive value. Smooth bromegrass (<i>Bromus inermis</i> Leyss.) and meadow bromegrass (<i>Bromus riparius</i> Rehm.) are the most commonly cultivated bromegrass species. Hybrid bromegrass (<i>B. riparius X B. inermis</i>) was developed in Canada by hybridizing smooth and meadow bromegrass. Regrowth potential differs among these three bromegrass species, but the morphological and physiological basis for these differences is unclear. Regrowth characteristics of three bromegrass species following defoliation to 5cm at the vegetative and stem elongation stages of growth were studied in the field and greenhouse. Above-and below-ground dry matter production, leaf area index (LAI) development, individual leaf area expansion, leaf-to-stem ratio, photosynthetic rate, tiller and axillary bud development, etiolated regrowth, and nitrogen concentration in stem bases were evaluated.<p> Regrowth was similar among the three species when defoliated at the vegetative stage. Meadow bromegrass consistently produced more (P¡Ü0.05) above-and below-ground dry matter than smooth bromegrass following defoliation at the stem elongation stage, while that of hybrid bromegrass was generally intermediate to the other two species. Individual leaf photosynthetic rates did not differ among the three species. Individual leaf area expansion rate was faster (P¡Ü0.05) in smooth bromegrass than meadow and hybrid bromegrass. LAI of the three bromegrass species increased linearly with days of regrowth (r2¡Ý0.88, P¡Ü0.05), and the increase was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass in all stages of defoliation. Similarly, the leaf-to-stem ratio was highest in meadow bromegrass, intermediate in hybrid bromegrass, and lowest in smooth bromegrass following all defoliations.<p> Defoliation at the vegetative stage had no effect (P¡Ý0.05) on tiller development relative to the undefoliated treatment, whereas tiller development was negatively affected by defoliation at the stem elongation stage. After 60 days of regrowth, final tiller density was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass in the field. A lower proportion of tillers in meadow bromegrass reached the reproductive stage compared to the other two species. The final tiller density following defoliation was similar among species in the greenhouse. Total buds tiller-1 and elongated buds tiller-1 were similar (P¡Ý0.05) among three species following defoliation at each growth stage; however, defoliation at stem elongation stage visually delayed bud development. Etiolated regrowth was greater in meadow and hybrid bromegrass (P¡Ü0.05) than smooth bromegrass 10 days after defoliation, but was similar thereafter. Concentration of N in stem bases was similar among species, but decreased with advancing maturity.<p> Rapid regrowth of meadow bromegrass appears to be associated with more tillers, rapid remobilization of organic reserves during early regrowth, and allocation of more biomass to leaf tissue than to stems compared to the other two bromegrasses. Variation in regrowth among the species was not associated with expansion of individual leaf area, photosynthetic rates, total organic reserve remobilization, or nitrogen concentration in stem bases. Based on these characteristics, meadow bromegrass is the most suitable species for grazing, and smooth bromegrass the least suitable.

Bromegrass species (<i>Bromus</i>) can produce high forage yields under the short growing season of western Canada and have excellent nutritive value. Smooth bromegrass (<i>Bromus inermis</i> Leyss.) and meadow bromegrass (<i>Bromus riparius</i> Rehm.) are the most commonly cultivated bromegrass species. Hybrid bromegrass (<i>B. riparius X B. inermis</i>) was developed in Canada by hybridizing smooth and meadow bromegrass. Regrowth potential differs among these three bromegrass species, but the morphological and physiological basis for these differences is unclear. Regrowth characteristics of three bromegrass species following defoliation to 5cm at the vegetative and stem elongation stages of growth were studied in the field and greenhouse. Above-and below-ground dry matter production, leaf area index (LAI) development, individual leaf area expansion, leaf-to-stem ratio, photosynthetic rate, tiller and axillary bud development, etiolated regrowth, and nitrogen concentration in stem bases were evaluated.<p> Regrowth was similar among the three species when defoliated at the vegetative stage. Meadow bromegrass consistently produced more (P¡Ü0.05) above-and below-ground dry matter than smooth bromegrass following defoliation at the stem elongation stage, while that of hybrid bromegrass was generally intermediate to the other two species. Individual leaf photosynthetic rates did not differ among the three species. Individual leaf area expansion rate was faster (P¡Ü0.05) in smooth bromegrass than meadow and hybrid bromegrass. LAI of the three bromegrass species increased linearly with days of regrowth (r2¡Ý0.88, P¡Ü0.05), and the increase was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass in all stages of defoliation. Similarly, the leaf-to-stem ratio was highest in meadow bromegrass, intermediate in hybrid bromegrass, and lowest in smooth bromegrass following all defoliations.<p> Defoliation at the vegetative stage had no effect (P¡Ý0.05) on tiller development relative to the undefoliated treatment, whereas tiller development was negatively affected by defoliation at the stem elongation stage. After 60 days of regrowth, final tiller density was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass in the field. A lower proportion of tillers in meadow bromegrass reached the reproductive stage compared to the other two species. The final tiller density following defoliation was similar among species in the greenhouse. Total buds tiller-1 and elongated buds tiller-1 were similar (P¡Ý0.05) among three species following defoliation at each growth stage; however, defoliation at stem elongation stage visually delayed bud development. Etiolated regrowth was greater in meadow and hybrid bromegrass (P¡Ü0.05) than smooth bromegrass 10 days after defoliation, but was similar thereafter. Concentration of N in stem bases was similar among species, but decreased with advancing maturity.<p> Rapid regrowth of meadow bromegrass appears to be associated with more tillers, rapid remobilization of organic reserves during early regrowth, and allocation of more biomass to leaf tissue than to stems compared to the other two bromegrasses. Variation in regrowth among the species was not associated with expansion of individual leaf area, photosynthetic rates, total organic reserve remobilization, or nitrogen concentration in stem bases. Based on these characteristics, meadow bromegrass is the most suitable species for grazing, and smooth bromegrass the least suitable.

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (<i>Bromus riparius</i>Rehm.), Carlton smooth bromegrass (<i>Bromus inermis</i>Leyss.) and AC Knowles hybrid bromegrass (<i>B. riparius</i> x <i>B. inermis</i>) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (<i>Agropyron cristatum </i> (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (<i>Festuca arundinacea </i> Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.

Meadow bromegrass (<i>Bromus riparius</i> Rehm.) is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it the most widely used grass species for pasturing beef animals in this region. As relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate genetic parameters and assess breeding methodologies for meadow bromegrass. Forty-four meadow bromegrass genotypes from the three available cultivars and forty half-sib (polycross (PX) and open-pollinated (OP)) and selfed (S1) progenies were evaluated for morphological and agronomic characters, and molecular (RAPD) markers. Genetic variation for total biological yield, head weight, seed yield, harvest index, height, growth habit, spread, and volume was significant in the OP and S1 tests. Genetic variation estimates for dry matter yield were negative (PX), not significant (OP), or moderate (S1). Estimated geneticvariation for quality traits and those characters which were visually evaluated was not significant, except for growth habit (OP and S1) and acid-detergent fiber (ADF) (S1). Among progeny lines, RAPD marker variation found in the half-sib progenies accounted for about 15% of the total variation. In the S1 test the variation among progeny lines was twice that of the half-sib progenies. Correlations between the different characters demonstrated that is possible to simultaneously improve both seed and forage yield. Since leafiness was found to be correlated with dry matter yield but not with seed yield it may be possible to simultaneously improve all three characters. Rankings of progenies by the half-sib tests for forage and seed yield were not changed by the use of the synthetic parental value (SVi) which includes information from selfed progeny. The PX progeny test did not discriminate parents as well as the OP and S1 tests, which may be due to non-random pollination in the polycross. The S1 progeny test showed the highest predicted response to selection, followed by the OP test. Heritability estimates from the OP and S1 tests for total biological yield, seed yield, harvest index, and height, were similar to those found in the clonal evaluation test. Therefore, a clonal evaluation test will provide sufficient information to choose parents for breeding an improved synthetic cultivar for these characters. Observed dissimilarity of ranking of progeny lines over progeny tests for some traits (head weight, seed yield, and harvest index) was due to discrepancies between the PX and OP tests. No differences in progeny line ranking among the progeny tests were observed for all other traits. Analysis of variance on marker frequency means showed that interaction between genotypes and progeny lines was also not significant.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1966. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Large populations of controlled hybrids are essential to the most rapid progress in many phases of plant breeding programs. Plant species vary in the ease with which they may be hybridized. Hand hybridization of forage grasses is usually slow and laborious, and the minuteness of the floral parts of most of the species which have perfect flowers renders their hybridization by hand especially difficult and tedious. This difficulty limits the use that forage grass breeders are making of the significant principles of hybridization and thereby retards progress in this phase of plant breeding. Any dependable, rapid technique of hybridization which would eliminate many of the present hand operations, that is "bulk" hybridization, would make possible more rapid progress in the breeding of forage grasses. The study herein reported was designed to estimate the feasibility of applying various methods of bulk emasculation and bulk pollination to forage grasses. In limiting the scope of the study, smooth bromegrass (Bromus inermis) was selected to receive the greatest attention because of its importance among forage grasses and the wide range of self-fertility among individual plants of the species, a characteristic which proved very helpful in the study.

Studies were conducted at three different sites in Saskatchewan, Canada (Colonsay, Vanscoy and Rosthern) over two years (2005 and 2006) to determine the effect of dribble banded and coulter injected liquid fertilizer applied in the spring of 2005 at 56, 112 and 224 kg N ha-1 with and without P at 28 kg P2O5 ha-1. A similar study was conducted in 2006 at one site in Mongolia to determine the effect of granular N and P fertilizer application on dry matter yield, and N and P concentration in plant biomass in the year of application (2006) only. The three Saskatchewan sites were unfertilized, 7-8 year old stands of mainly meadow bromegrass (<i>Bromus riparius</i>) dominated haylands, while the Mongolia site was mixed species of native rangeland.<p>All fertilization treatments produced significantly (p≤0.05) higher dry matter yield than the control in the year of application at the three Saskatchewan sites. The addition of 28 kg P2O5 ha-1 P fertilizer along with the N fertilizer did not have a significant effect on yield in most cases. In the year of application, increasing N rates above 56 kg N ha-1 did not significantly increase yield over the 56 kg N ha-1 rate in most cases but did increase N concentration, N uptake and protein content. A significant residual effect was found in the high N rate treatments in 2006, with significantly higher yield and N uptake. In 2005, the forage N and P uptake were in all cases significantly higher than the control in the fertilized treatments. The N uptake at the three Saskatchewan sites increased with increasing N rate up to the high rate of 224 kg N ha-1, although the percent recovery decreased with increasing rate. The P fertilization with 28 kg P2O5 ha-1 also increased P uptake at the three Saskatchewan sites. The site in Mongolia was less responsive to fertilization than the three Saskatchewan sites, with only a significant response in yield, N uptake and no significant effect of P fertilization. <p>For incubation soil cores collected in the fall of 2006, mean respiration rates were similar among the fertilized treatments at all the sites and the pattern of CO2 and N2O evolution measured over a two-week period showed similar trend at the three sites, with no significant difference between treatments. However a significant increase in gas production occured as the soils were wetted during the incubation. By the fall of 2005, the fertilization effect had likely diminished along with available substrate for the soil microbial biomass.<p>Overall, rates of fertilizer of approximately 50 kg N ha-1 appear to be sufficient to produce nearly maximum yield and protein concentration of the grass in the year of application for the Saskatchewan and Mongolia sites. Surface banding placement was as effective as in soil placement and there was limited response to P fertilization. A small amount of N fertilizer that is surface-placed on these grass dominated forage systems appears to be an effective means of increasing production in the year of application. Higher rates are needed to sustain the rejuvenation beyond one year.

Studies were conducted at three different sites in Saskatchewan, Canada (Colonsay, Vanscoy and Rosthern) over two years (2005 and 2006) to determine the effect of dribble banded and coulter injected liquid fertilizer applied in the spring of 2005 at 56, 112 and 224 kg N ha-1 with and without P at 28 kg P2O5 ha-1. A similar study was conducted in 2006 at one site in Mongolia to determine the effect of granular N and P fertilizer application on dry matter yield, and N and P concentration in plant biomass in the year of application (2006) only. The three Saskatchewan sites were unfertilized, 7-8 year old stands of mainly meadow bromegrass (<i>Bromus riparius</i>) dominated haylands, while the Mongolia site was mixed species of native rangeland.<p>All fertilization treatments produced significantly (p≤0.05) higher dry matter yield than the control in the year of application at the three Saskatchewan sites. The addition of 28 kg P2O5 ha-1 P fertilizer along with the N fertilizer did not have a significant effect on yield in most cases. In the year of application, increasing N rates above 56 kg N ha-1 did not significantly increase yield over the 56 kg N ha-1 rate in most cases but did increase N concentration, N uptake and protein content. A significant residual effect was found in the high N rate treatments in 2006, with significantly higher yield and N uptake. In 2005, the forage N and P uptake were in all cases significantly higher than the control in the fertilized treatments. The N uptake at the three Saskatchewan sites increased with increasing N rate up to the high rate of 224 kg N ha-1, although the percent recovery decreased with increasing rate. The P fertilization with 28 kg P2O5 ha-1 also increased P uptake at the three Saskatchewan sites. The site in Mongolia was less responsive to fertilization than the three Saskatchewan sites, with only a significant response in yield, N uptake and no significant effect of P fertilization. <p>For incubation soil cores collected in the fall of 2006, mean respiration rates were similar among the fertilized treatments at all the sites and the pattern of CO2 and N2O evolution measured over a two-week period showed similar trend at the three sites, with no significant difference between treatments. However a significant increase in gas production occured as the soils were wetted during the incubation. By the fall of 2005, the fertilization effect had likely diminished along with available substrate for the soil microbial biomass.<p>Overall, rates of fertilizer of approximately 50 kg N ha-1 appear to be sufficient to produce nearly maximum yield and protein concentration of the grass in the year of application for the Saskatchewan and Mongolia sites. Surface banding placement was as effective as in soil placement and there was limited response to P fertilization. A small amount of N fertilizer that is surface-placed on these grass dominated forage systems appears to be an effective means of increasing production in the year of application. Higher rates are needed to sustain the rejuvenation beyond one year.